How to Determine Condensation from Water Penetration on a Wall

There is a very simple test to determine whether or not the wetness on a wall is from external water penetration through the wall or from condensation depositing moisture on the wall.  If you encounter a situation where you need to determine what caused a wall to be wet you can follow the below steps:

  1. Pick a test area on the wall and take measures to adequately dry the wall.  This can be done with heaters or any other safe method that restores the area to a dry state.
  2. Once dry, take a piece of aluminum foil and tape it onto the wall in the area that you have dried.  Be sure to tape all of the sides so that you reasonably seal the air behind the foil.
  3. Leave the foil in place for at least a day and then remove it. If the moisture is on the side of the foil facing away from the wall, it is condensation. If it is on the side of the foil facing the wall, it is penetration through the wall.

How to Reduce Condensation or Dampness in the Basement

  1. Allow moisture to move out of the home when cooking or washing or drying clothes.
  2. Make sure the bathroom is ventilated to allow hot steam to exit the home after baths and showers.
  3. Insulate the basement by air sealing and installing additional insulation as needed in areas of concern.
  4. Check the basement for water penetration issues.